[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: init requires /dev/vc devices

* Rob Landley <rob@landley.net> [2006-02-15 12:12]:
> Lemme see if I understand this:
> You have an inittab telling busybox init to spawn things on three consoles
> that either don't exist when you run init,

No, they do exist because we create them before running init.

> or are invalid device nodes.

Right, on some devices they are invalid device nodes because we have
to create them before init starts.  If we don't create them before init
starts, the following from inittab will be ignored:

vc/3::respawn:/usr/bin/tail -f /var/log/messages
vc/4::respawn:/usr/bin/tail -f /var/log/syslog

> The current busybox init is not failing gracefully when you do this.

> That's a sequencing issue.  Whoever wrote this didn't expect the sysinit 
> script to completely redo the contents of /dev.  If I can get it clear in my 
> head exactly what you want to do, I can take a whack at fixing it.

Basically, we use udev.  However, we have to manually create /dev/vc/*
before init is started because busybox doesn't behave properly if this
doesn't exist.  What I'd like to see is that we only have to create
/dev/vc/0 and vc/1, then start init, then run udev which will (or not)
crate /dev/vc/2-4.  Current bb init doesn't allow this because it will
ignore the above vc/3|4::respawn statements if those devices don't
exist _by the time_ init is started.  And init -q doesn't seem to
work, so we cannot start with a minimal inittab and then add more
later and tell init to spawn it.

> In the short term, there are a few possible workarounds.  You could
> have your wrapper figure out whether or not it needs to create the
> device nodes before calling /init.

Yeah, that's what we thought too.  Colin tried to implement this but
he said our script to figure out whether we're on a serial console
doesn't work at that point.
Martin Michlmayr

Reply to: